Q: Our Sixties semi-detached house has suspended floors downstairs. As the living room is the coldest in the house we hit on the idea of lifting the floorboards, adding insulation and then replacing the boards. A messy job, but not one beyond the ability of a reasonably competent DIYer.

South Somerset District Council say they offer advice on home insulation, so I called them. Not much advice was forthcoming other than that to lift a floor and put it back down would constitute a “renovation of a thermal element”, which would require a “Building Notice” for which the local council would be happy to relieve me of at least £125.

They did promise to send some information about insulation, but all I got was the Building Notice application form and a list of charges. Raising revenue seems to be more important than offering people advice, and paying an extra £125 has rendered the whole exercise less than worthwhile.

Is it true that councils can make such high charges for relatively small jobs such as this? If so it seems to make a mockery of the claims both they and the Government make about wanting to encourage people to insulate their homes.

A: I have advised readers several times over the past few years that insulating below suspended timber ground floors is a great way of improving a home’s comfort and cutting heating bills. In my opinion, there is no need to apply for Building Control approval to do this, and I think your local authority has got it wrong.

The “renovation of thermal elements” jargon first appeared in the Building Regulations in 2006. In order to inveigle owners into improving the insulation of older buildings, it was decided that when 25 per cent or more of a wall, roof or floor was being renovated, its thermal insulation should be upgraded at the same time – to the same value that applies to new buildings.

This is actually a bad idea, because when a building or room is only partially insulated, it will increase the risk of condensation on the uninsulated parts. However, the government department responsible (which changes its name frequently, but is currently the Department for Communities and Local Government) persisted, and tinkered with the rules. So the 25 per cent figure became 50 per cent in 2010, and then it was decided it wouldn’t be 50 per cent of the whole wall or floor area of the building, but 50 per cent of that area within a particular room.

Things have become so confusing that different local authorities now enforce the rule in different ways. Some say that thermally improving a floor by lifting the boards, inserting insulation and replacing the boards is not a “renovation” (but that if you fitted new floorboards, it would be). Others, like yours, seem to have a different view.

In any case, this regulation is supposed to encourage upgrading of the thermal insulation of the nation’s housing stock – not to penalise people like you, who have decided to insulate anyway and are being threatened with a “fine” for so doing.

I find it hard to disagree with your view that your local authority is using this as a moneymaker. Local Building Control departments have lost out since the opening up of Building Control to private approved inspectors, and they do seem to be constantly looking for ways to levy fees.

The simple way around it in your case would be to lift only 50 per cent of the floorboards, and to push the insulation into place through the gaps. This is fiddly, of course, and not ideal, as it means you can’t lay a continuous vapour barrier across the whole floor before refitting the boards.

The national Building Regulations for England and Wales was a set of documents first published in 1966 with a noble purpose. The original authors must be astonished at the way their work is being brought into disrepute, largely by “man-made climate change” zealots.

The minister currently in charge is Eric Pickles, a man who is no stranger to knocking a few heads together. Let’s hope he will bring pressure to bear to resolve this anomaly.